Grinding tool



March 10, 1942.

R. F. CLEARY 2,275,889

GRINDING TOOL Original Filed April 20, 1939 ATT ORNEY.

Patented Mar. 10, 1942 UNHTED STATES I QFFICE 2 Claims.

This invention relates to a novel tool for shaping the Bunsen burnerelements of gas heaters, stoves and the like; this application being adivision of my copending application Ser. No. 268,868, filed April 20,1939.

In Bunsen burners for gas fuel burning apparatus, the production of thedesired mixture of combustible gas and air is most efficiently attainedby providing, between the gas and air intakes and the burner jets, arestricted throat of the Venturi tube type. The gas is admitted axiallyto the Venturi throat, while the air is admitted through ports of an airshutter cap radial to the gas admission means. For highest mixingefficiency, it is necessary that the Venturi tube throat be bothaccurately aligned axially relative to the gas admission port as well asin perfectly true concentric relation thereto at all times. Since,however, in gas heaters, stoves, and the like, as commonly manufactured,the burner fixture, which includes the Venturi portion, is usually madeof cast iron, warping of this metal when the casting thereof cools, aswell as the roughened and imperfect surfaces left by the sand of thecasing molds and cores, tends to leave both the internal and externalsurfaces of the burner fixture casting deformed and rough. By reason ofthis it is exceedingly difiicult to fit the air shutter cap, whichcarries the gas admission valve, to the outer flared end of the fixture,so as to attain and maintain the desired axially aligned andconcentrically true relation of the gas admission port to the Venturithroat passage. Any surface imperfections and roughness of therestricted areas of the Venturi throat passage also tend to defeatattainment of said desired axially aligned and concentrically truerelations, even though the fixture end be machined for fitting the airshutter cap to its face and periphery. Attempts have been made toseparably machine the face and periphery of the fixture end, and then toseparably bore out the Venturi throat passage, but the results of saidseparate operations have not been successfully coordinated so as toattain the desired relations sought, and so that said relations areassured at all adjusted positions of the air shutter cap.

Having the above stated conditions in view, the present invention hasfor an object to provide a novel tool for shaping the burner fixture,whereby the face and periphery of its air shutter cap receiving end andthe Venturi throat passage thereof are simultaneously ground so as torelatively coordinate the resulting surfaces whereby the face is trulyperpendicular to the axis of the Venturi passage while the periphery isconcentrically true to said axis,'and at the same time the restrictedareas of the Venturhthroat passage are likewise concentrically true tosaid axis.

Other objects of this invention, not at this time more particularlyenumerated, will be understood from the following detailed descriptionof the same.

Illustrative embodiment of the invention is shown in the accompanyingdrawing, in which- Fig. l is a perspective view of the novel tool ofthis invention which is adapted to simultaneously grind and shape thevarious surfaces of the burner fixture desired to be coordinatelyrelated.

Fig. 2 is a longitudinal sectional view of a portion of the burnerfixture with said tool operatively applied thereto, said tool also beingshown in part section.

Fig. 3 is a fragmentary longitudinal sectional View with parts inelevation showing the burner fixture as ground and shaped by said tool.

Similar characters of reference are employed in the above describedviews, to indicate corresponding parts.

Gas burner fixtures comprise a hollow main body (not shown) of anysuitable external and internal shape, to provide an internal fuelmixture supply chamber from which lead the gas burner jets or tips, allas well known to the art. Extending outwardly from the main body is thefuel mixture intake arm It, the passage M of which tapers to arestricted Venturi throat l5, thence flaring outwardly to provide aflared outer end portion H5. The flared outer end portion I6 is providedwith an end wall ll, transverse to the longitudinal axis of said intakearm t3, the same terminating in an exteriorly projecting annular flangel8 surrounding said flared outer end portion. Said end wall I! isprovided with a central opening l9, extending from which, in oppositeradial directions, are air intake openings 20. Mounted on the outer endof the intake arm 13, so as to be rotatably adjustable thereon, is anair shutter cap 2 I, said cap having a projecting skirt flange 22 toengage over the peripheral surface 23 of said flange 3 with which theouter end of said intake arm is provided. On its exterior face, said capis provided with a central outwardly projecting hub 24, provided with anaxial bore 25 to receive the discharge end portion 25 of a gas deliveryvalve 21,. which is adapted to be inserted therein in swiveling relationthereto. Formed in said cap, outwardly of said hub 2 are oppositelyextending. radial air port openings 23 which cooperate with the airintake openings 20 in the end wall I! of said intake arm l3. Threadedinto said end wall I! are screw and washer fastening means 29, thewasher of which engages the air shutter cap 2|, so that, when screwedhome, the latter will be secured in desired adjusted position whereinthe respective openings and 28 will be so lapped as to provide aproperly determined area of air intake opening leading into the intakearm. The gas delivery valve is provided at its discharge end portion 26with an axial gas port element 30, cooperative with which is anadjustable needle valve 3|, for regulating the discharge of gastherethrough. To provide the desired swiveling relation between the gasdelivery valve 27 and the air shutter cap 2 I, the discharge end portion26 of the former is provided with an annular stop shoulder 32 to engagethe exterior end of the hub 24 of the latter, to thereby limit inwardaxial movement of said gas delivery valve. Said end portion 26 isprovided with an external annular channel 33 into which enters, from theair shutter cap 2|, the end of a retaining screw 34 for holding the gasdelivery valve and air shutter cap 2! in swiveling relation.

In order to assure that the exterior face of r the end wall I! of theintake arm l3 (against which the air shutter cap 2| abuts) is trulyperpendicular to the longitudinal axis of said intake arm, while at thesame time assuring that the periphery of said end wall (formed by theannular surface 23 of the flange l8) and the internal contour of theVenturi throat I5 are both concentrically true to said axis, theserespective surfaces are subject to a novel method of treatment wherebythe same are simultaneously ground. To this end, a novel combinationtool is provided having a plurality of cutting elements so related as tooperatively and simultaneously engage the respective surfaces to beground when the tool is rotated in contact with the work.

Said tool comprises a body 35 having a tail piece or shank 36 formounting the same in a suitable driving mechanism. At its forward endsaid tool body 35 is provided with an outwardly open socket 31, in whichis inserted and secured, as by a set screw 38, a face grinding member39, the radial cutting teeth of which lie in a plane perpendicular tothe axis of rotation of the tool. Said face grinding member 319 and thetool body 35 are provided with connecting axial bores 40 and 4! toreceive the tail shank 42 of an axially disposed reamer member 43, whichis thus arranged to project forwardly beyond said face grinding member.Said reamer member is secured to the tool body 35 by a set screw 44which extends laterally therethrough into holding engagement with saidreamer member tail shank 42. Formed in the external sides of the toolbody 35 are one or more longitudinal sealing channels 45 in which areseated cutter tools 46, the operative ends of whichproject beyond thesaid face grinding member, with their effective cutting edges lyingparallel to the axis of rotation of the tool. These cutter tools areadapted to operatively engage the peripheral annular surface 23 of theintake arm end. Said cutter tools are held in place by clamp plates 4'!affixed to said tool body by screws 48 or other suitable fasteningmeans.

When the tool is operatively rotated, the free end of the intake arm l3of a burner casting is applied thereto, whereby, while the reamer member43 enters and grinds the Venturi throat IS, the face grinding membergrinds the face of the intake arm end wall l1, and the cutter tools 45engage and grind the external annular peripheral surface 23 of theintake arm end. Since the several grinding members or tools are socoordinated as to maintain their relations to the axis about which thetool rotates, when the face grinding member 39 operatively contacts theend wall surface of the intake arm and the reamer member 43simultaneously enters and reams out the Venturi throat l5, said end wallsurface will of necessity be faced to a plane truly perpendicular to theaxis of the intake arm, while the internal contour of the Venturi throatl5 will be ground to concentrically true relation to said axis. At thesame time, the external annular peripheral surface 23 of the intake armend will likewise be ground to concentrically true relation to the axisof the intake arm.

The face of the intake arm end ll being, by the described grindingoperations, trued to a plane perpendicular to the axis of said arm,while the external peripheral surface 23 of the intake arm end is madeconcentrically true to said axis, when the air shutter cap 2| is appliedto said intake arm end, not only will the gas port 30 be accuratelyaligned with the axis of the intake arm passage, but all risk ofdisturbing such accurate alignment, during or by r0- tative adjustmentof the air shutter cap, is avoided; and, at the same time the Venturithroat I5 is assured of being in true concentric conformity to the axisof said intake arm, as well as in true axial alignment with the gasdelivery port 30.

Having described the present invention, and the advantages thereof, Iclaim:

1. A tool for the purposes described compris ing, a rotatable carrierbody having a forwardly open axial socket, a cylindrical wall facegrinding member the rearward portion of which is adapted to be securedwithin said socket, said grinding member having a cutting face at itsforward end disposed in a plane perpendicular to the axis of saidcarrier body, an axial reamer member forwardly projecting from thecutting face of said grinding member, said carrier body having seatingchannels in its periphery, and wall edge cutters affixed in saidchannels so as to dispose their effective cutting portions about theperiphery of said Wall face grinding member and in overhanging relationto the cutting face thereof.

2. A tool for the purposes described comprising, a rotatable carrierhaving a forwardly open axial socket and a rearwardly extending axialtail shank, a cylindrical wall face grinding member the rearward portionof which is adapted to be removably secured within said socket, theforwardly presented end face of said grinding member having a pluralityof radiating cutting elements the operative edges of which lie in acommon plane perpendicular to the axis of said carrier body, saidgrinding member and said carrier body having aligned axial bores, areamer member projecting forwardly beyond the cutting face of saidgrinding member and having a tailpiece extending rearwardly through saidbores adapted to be removably secured to said carrier body, said carrierbody having seating channels in its periphery, and wall edge cuttersremovably aflixed in said channels so as to dispose their effectivecutting portions about the periphery of said grinding member and inoverhanding relation to the cutting face thereof.

RICHARD F. CLEARY.

